- LR-S: Patients receive vincristine IV on days 1 and 8, oral dexamethasone on days 1-14, pegaspargase IV over 2 hours on day 9, cyclophosphamide IV over 30 minutes on day 22, cytarabine IV or intramuscularly (IM) on days 23-26, oral thioguanine on days 22-28, and methotrexate IT on days 1, 22, and 36.